RTPU FR
Flame-retardant grade
also Isoplast
FR = flame-retardant (UL 94 V-0) grade
Use for electrical enclosures, connectors and rail/transport parts needing V-0 at 1.5–3 mm; slight loss of impact and elongation.
Values for the FR condition
Other RTPU grades and fills
RTPU is listed in 6 conditions; see the grade overview at RTPU.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
FRThis page Flame-retardant (UL 94 V-0) grade | Use for electrical enclosures, connectors and rail/transport parts needing V-0 at 1.5–3 mm; slight loss of impact and elongation. | 46 | 50 | 80 | 79 Shore D |
ESD / antistatic compounded grade | Carbon-black or permanent-antistat filled compound for tool housings and handling parts needing static dissipation. | 47 | 50 | 50 | 80 Shore D |
Hydrolysis / chemical-resistance stabilised grade | Polyether or carbodiimide-stabilised chemistry for hot-water, humid or fuel/oil-contact service (e.g. oilfield and plumbing parts). | 50 | 55 | 160 | 76 Shore D |
10 % glass-fibre reinforced | Mild stiffening step that keeps useful ductility and impact strength; good for housings needing better creep resistance. | — | 72 | 25 | — |
20 % glass-fibre reinforced | Balanced stiffness/toughness reinforcement for load-bearing brackets and pressurised fittings. | — | 95 | 8 | — |
30 % glass-fibre reinforced | Highest stiffness and strength grade; pick for metal-replacement structural parts where impact demand is moderate. | — | 115 | 5 | — |
What is RTPU FR?
RTPU FR is RTPU in the FR grade — use for electrical enclosures, connectors and rail/transport parts needing V-0 at 1.5–3 mm; slight loss of impact and elongation. RTPU FR has a yield strength of 46 MPa (6.67 ksi) and a tensile strength of 50 MPa (7.25 ksi) — weaker than 55% of polymer grades. Elongation at break is 80% and the elastic modulus is 2.3 GPa (0.334 Msi). RTPU FR has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 100°C (212 °F).
RTPU FR properties
Typical room-temperature values for RTPU FR; 27 are specific to this condition. Other listed values are RTPU reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
RTPU FR has a density of 1.3 g/cm³ (0.047 lb/in³), heavier than 69% of polymer grades. Its glass-transition temperature is 100°C (212 °F).
Mechanical13
RTPU FR has a yield strength of 46 MPa (6.67 ksi) and a tensile strength of 50 MPa (7.25 ksi) — weaker than 55% of polymer grades. Elongation at break is 80% and the elastic modulus is 2.3 GPa (0.334 Msi).
Thermal11
RTPU FR is rated for continuous service to 75°C (167 °F). It conducts heat at 0.23 W/m·K (0.133 BTU/hr·ft·°F), better than 65% of polymer grades. Thermal expansion is 85 µm/m·K (47.2 µin/in·°F).
Electrical7
RTPU FR is an electrical insulator with a dielectric strength of 24 kV/mm (609.6 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (78/100), worse than 61% of polymer grades. UV resistance is fair.
Sustainability4
Producing a kilogram of RTPU FR takes about 118 MJ of energy and emits 5.5 kg of CO₂ — more than 72% of polymer grades. Typical recycled content is 0%.
Manufacturability8
RTPU FR's machinability is good (58/100, worse than 55% of polymer grades); weldability good (62/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with RTPU FR
Is RTPU easy to machine?
Machines like tough PC: sharp positive-rake carbide tools, high speed with low feed and air/mist cooling to avoid gumming and stress whitening; anneal stock before tight-tolerance cuts.
Can RTPU be welded?
Joins well by ultrasonic, hot-plate, spin and RF welding, and bonds with polyurethane/cyanoacrylate or solvent-type adhesives after light abrasion.
Can RTPU be formed, bent or molded?
Dry pellets 2–4 h at 90–100 °C to <0.02 % moisture, mould at 200–235 °C melt / 20–60 °C tool with generous gates; sheet thermoforms near 150–170 °C.
What surface finishes work on RTPU?
Takes paint and PU topcoats readily after adhesion promoter; can be pad-printed, laser-marked, vacuum-metallised or textured — avoid strong ketone/chlorinated solvent cleaners.
RTPU chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| 4,4'-MDI (diphenylmethane diisocyanate hhigh hard-segment content gives rigidity | 45 – 65 | 55 |
| short-chain diol chain extender (1,4-but | 15 – 30 | 25 |
| additives (antioxidant, UV stabiliser, l | 0.2 – 2 | 0.8 |
| glass fiber0 in default unfilled grade; 10/20/30 % in GF variants | 0 – 30 | 0 |
| polyol soft segment (polyether PTMEG or polyether for hydrolysis resistance, polyester for oil/abrasion | ≥ 10 (balance) | — |
RTPU FR — frequently asked
What is RTPU FR used for?
RTPU FR is typically used for power tool housings, ski boots and sporting goods, automotive interior trim, medical device housings and industrial rollers. In short: stiffest thermoplastic polyurethane; tough chemical-resistant housings; PC-like rigidity, higher toughness.
What is the yield strength of RTPU FR?
RTPU FR has a typical yield strength of 46 MPa (6.67 ksi) and a tensile strength of 50 MPa (7.25 ksi) — weaker than 55% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is RTPU FR easy to machine?
Reasonably — machinability is rated good (58/100, worse than 55% of polymer grades). Machines like tough PC: sharp positive-rake carbide tools, high speed with low feed and air/mist cooling to avoid gumming and stress whitening; anneal stock before tight-tolerance cuts.
Can RTPU FR be welded?
Yes — weldability is rated good (62/100). Joins well by ultrasonic, hot-plate, spin and RF welding, and bonds with polyurethane/cyanoacrylate or solvent-type adhesives after light abrasion.
What surface finishes work on RTPU FR?
Takes paint and PU topcoats readily after adhesion promoter; can be pad-printed, laser-marked, vacuum-metallised or textured — avoid strong ketone/chlorinated solvent cleaners.
Can RTPU FR be formed, bent or molded?
Dry pellets 2–4 h at 90–100 °C to <0.02 % moisture, mould at 200–235 °C melt / 20–60 °C tool with generous gates; sheet thermoforms near 150–170 °C.
What is the maximum service temperature of RTPU FR?
RTPU FR is rated for continuous use to about 75°C (167 °F), and briefly to 110°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Isoplast Engineering Thermoplastic Polyurethane Resins — product and processing data — Lubrizol Engineered Polymers (2022)
- CAMPUS / UL Prospector rigid TPU (TPU-ARES/TPU-ARET) datasheets — CWFG / UL Solutions (2024)
- ASM Engineered Materials Handbook Vol. 2 — Engineering Plastics (polyurethanes) — ASM International (1988)
- ISO 527 / ISO 178 / ISO 75 / ASTM D256 test methods — ISO / ASTM (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.